drm/i915: parameterize SDE hotplug registers

Ice Lake, Tiger Lake and Elkhart Lake all have different port
configurations and all of them can be parameterized the same way to form
the SDE hotplug bitmask. Avoid making them a special case an just use
the parameterized macros.

Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190829211526.30525-3-jose.souza@intel.com
Signed-off-by: José Roberto de Souza <jose.souza@intel.com>